Moose habitat use and activity in Voyageurs National Park

Students: William Chen, Tessa Tjepkes, Amanda McGraw, Michael Joyce.

Status: Home range analysis is complete and habitat use analysis is near completion. William Chen, former Ph.D. student, withdrew from the graduate program before finishing manuscripts. Because of uncertainties with data handling and calculations, I had Michael Joyce (grad student) redo analyses.

From 1990 to 2005, moose (Alces alces) counted in the aerial survey declined from at least 4,000 to fewer than 100 animals in northwest Minnesota. Annual moose mortality was high, at 21%, and moose pregnancy and recruitment rates were very low. Mortality was attributed to health-related issues correlated with increased summer and winter temperatures. The aerial count of moose in northeast Minnesota declined from about 8,000 to about 4,000 animals, with health-related issues and predation mortality likely causes.

Voyageurs National Park (VNP) is halfway between the NE and NW moose populations in Minnesota. Moose in VNP have remained relatively stable while other populations in Minnesota declined. In this research project we deployed GPS collars on moose in VNP to evaluate changes in habitat use as related to changes in ambient temperature. GPS collars collected locations at 20 minute intervals and transmitted those locations via the Argos satellite network.

We collected over 660,000 locations on 25 different moose moose in VNP from 2010 to 2013. We retrieved collars in February, 2013 after the collar drop-offs failed to trigger. Seasonal and annual home ranges of moose in VNP were similar in size to home ranges in NE Minnesota (e.g., annual MCP home range 18±2 (mean±SE) compared to 26±2 for VNP in early 1990’s, 28±3 for northeast Minnesota, 30±3 for northeast Minnesota ). Winter home ranges were smaller than summer home ranges.

We used bedsite locations from moose in VNP identified from GPS collar locations to evaluate bedsite selection. Daytime bedsites were on wet substrates in wetter cover types with canopy cover when temperatures were hotter in summer. Bedsites at night were under lower canopy cover regardless of temperatures.

The other part of analysis that is being redone is the cover type composition and use across the range of temperatures in each season. Cover type use is being compared to historical GPS collar data from VNP (1995-1997) and this research project (2010-2012). While redoing the analysis, we are incorporating results of a 2014 M.S. thesis by Bryce Olson on the thermal landscape at VNP.


Final Report: Final Report: Moose habitat use in Voyageurs National Park